The Transportation Security Administration (TSA) is using body-scanning units at a number of U.S. airports. Two types of technology are used in body-scanning machines.
- Millimeter-wave technology does not use x-rays, but rather uses low-level radio waves to scan a person’s body. A millimeter-wave body scanner uses two antennas that rotate around a person’s body to construct a 3-D image that resembles a fuzzy photo negative. The image is sent to a remote monitor.
- Backscatter technology uses weak x-rays to create a two-sided scanning image that is sent to a monitor. These x-rays do not penetrate much beyond the skin, but they can show objects hidden under clothing. Backscatter technology creates images that look like chalk drawings. This technology exposes a person to about as much radiation as a 2-minute airplane ride at 30,000 feet.
The National Council on Radiation Protection and Measurement (NCRP) has found that the dose from backscatter scans is about 100,000 times less than what a person receives from natural background radiation in one year. Background radiation is what we receive naturally from the earth and cosmic sources. The Centers for Disease Control and Prevention (CDC) supports the NCRP’s position that the health risk from airport full-body scanning is low.
CDC does not conduct research or set standards for any radiation-related activity concerning human screening devices in airports. However, the following safety measures ensure that scanner operators and travelers who are scanned are protected.
- The U.S. Food and Drug Administration has federal authority to set standards for x ray systems.
- The Nuclear Regulatory Commission has federal authority over the purchase and use of radioactive materials.
- The Occupational Health and Safety Administration has federal authority to set exposure limits and requirements to protect workers who handle radioactive materials or use devices that release radiation.
- The Health Physics Society recommends that the use of screening systems should conform to the American National Standards Institute dose-limit requirements for scanners when the practice is used to screen members of the general public.
In addition to these specific requirements or recommendations, state and local requirements may exist that regulate installation, maintenance, operation, registration, and licensing of these systems. State or local public health or environmental agencies will have more information on these requirements.